I have figured out the Richtofen maze crap. It's not random, it is shown to you. For me, I had the new perk, and usually I can see everything from far away right? Well not during this part, I could only see Quick revive and Pack-A-Punch light up. So that led me to think that the combo is either BYGR or YGRB. Tried BYGR with no avail, then did YGRB and it finished. Just make sure you have the new perk and it is shown.
Other players had other ones light up, but we didn't dig too deep into it. I recommend using the one who has pack-a-punch shown do it, so it is easier to figure out.
Also Vulture-Aid did light up, but only once inside the church, so I ignored it.
We also didn't finish the whole thing because my buddy disconnected right before I figured it out, so I will test again tomorrow.